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A UNITED STATES PATENT OFFICE,

JAMES FOLEY, OF MONTREAL, QUEBEC, CANADA.

TANNING COMPOUND.

SPECIFICATION forming part of Letters Patent No. 237,007, dated January 25, 1881.

Applioationfiled November 3, 1880. (No specimens.)

To all whom it may concern:

Be it known that I, JAMES FOLEY, of the city of Montreal, in the Province of Quebec, Canada, have invented certain new and useful Improvements in Aqueous Solutions of Tannin or Tanning-Ooze; and I do hereby declare the following to be a full and complete description of the same.

This invention has reference to the preservation and protection of tannin or tannic acid from the deteriorations to which it is subject in aqueous solutions and in tanning extracts prepared from bark and other tanning materials, and to the modification of the red colorin g-matters in tanning-ooze; and the object of my said invention is to preserve and protect the tannic acid in tanning solutions or ooze and in semi-liquid tanning extracts from decomposition and conversion into gallic acid, to modifythe red coloring-matter in tanning solutions or ooze and its effect upon the tanned leather.

The various kinds of bark and tanning materials yield (apart from the tannic acid) a variety of soluble extractive matters which exist in the ooze with the tannic acid. These extractive matters are capable of inducing fermentation in the solution or ooze, the decomposition of the tannic acid, and its conversion into gallic acid, which is not absorbed by the hides or skins, thus causing a material loss to the tanner. These extractive matters also produce a red colorin g-m atter in the tannin g-ooze, which becomes permanently attached to the hide while being tanned, and gives an objectionable red color to the finished leather and to its grain when buffed, which depreciates its value. This coloring-matter seems to be generated through a kind of fermentation in the tanning-ooze, which comes on suddenly both in cold and warm weather, but more particularly in the latter.

- Through extensive practical experiments I have found that by the incorporation of a concentrated liquor or extract, varying in density from 10 to 60 Twaddle, obtained from the wood of the Moms ttnctom'a, the decomposition of the tannic acid and its conversion into gallic acid is prevented, the formation of the red coloring-matter checked, and its effect upon the hides in the process of tanning is so modified that a leather light in color throughout its entire thickness, with a grain of a good oak color, is produced, which will command at least ten to fifteen per cent. higher price than can be obtained for the red leather now made.

I incorporate the concentrated liquor or extract obtained from the wood of the Moms tinctoria, by adding it to tanning solutions or ooze prepared from all kinds of tanning materials. The quantity will vary according to the varying strengths of the tanning solutions or ooze. I have found the following proportions to be the most effective and economical for general use, viz: To every one hundred gallons of the tanning solution or ooze of from 6 to of strength by what is termed the barkometer 1 add one gallon of the concentrated liquor or extract obtained from the wood of the Moms tinctom'a if its specific gravity is from 40 to 50 Twaddle, and one and one-half gallon if the specific gravity is from 12 to Twaddle; and if the tanning solution or ooze is from 20 to of strength by the barkometer, I add one and one-half gallon of the liquor or extract from the wood of the Moms tinctom'a, if of 40 to Twaddle, and two gallons if 12 to 20 Twaddle, to every one hundred gallons of the tanning solution or ooze, thoroughly incorporatin g them together.

The concentrated liquor or extract obtained from the wood of the Morus'tt'nctom'a may be added to or incorporated with semi-liquid tanning extracts in the proportion of twenty pounds, in weight, of the specific gravity of 50 to Twaddle, to every one hundred pounds, in weight, of the semi-liquid tanning extract, to preserve it from the hereinbeforementioned deteriorations and to modify the colorin g-m atter therein. The exact proportions are not material to the successful carrying out of my said invention.

Aqueous solutions of tannin or tanning-ooze in which the concentrated liquor or extract obtained from the wood of the Moms tinctoria is incorporated may be concentrated to a semiliquid state by any suitable method employed for concentrating fluids.

By the incorporation of the concentrated liquor or extract obtained from the wood of the Moms ttnctom'a with tanning-ooze a large sav ing is efiected in the consumption of tannic wood of the Moms tinctom'a is incorporated, as 10 and for the purpose set forth.

In testimony that I claim the foregoing I have hereunto set my hand this 29th day of October, 1880.

JAMES FOLEY. Witnesses:

ELMER J. MORGAN, GEO. A. GOODYEAR. 

